Add prominent links to existing presentations (slides) and videos

[hjacobs]

It would be really valuable to have a prominent section with links to existing presentations about the STUPS ecosystem, e.g.:

• STUPS by Zalando @ AWS Berlin User Group Meetup May 2015: http://www.slideshare.net/try_except_/stups-by-zalando-aws-2015-0521awsugmaymeetup
• DevOps Con 2015: Radical Agility with Autonomous Teams and Microservices in the Cloud: http://www.slideshare.net/try_except_/dev-ops-con-2015-radical-agility-with-autonomous-teams-and-microservices-in-the-cloud?related=1
• DevOps Con 2015 recorded talk: https://www.youtube.com/watch?v=IujDeMdXAgA

I guess these presentations will help people to get started with STUPS.

[hjacobs]

TODO: add link to Eric's AWS Berlin Summit keynote (YouTube)